This game is fun: Tag. It could be how the paint works in Portal 2, although obviously you won't have a paint-spraying gun. Still, a great game. A bit short, but that's understandable, since it's a school project.

Spelunky will feel strangely familiar to people who stuck with La Mulana for a while, and to people who brave the many roguelikes. Great platform game with a certain learning curve to it. I'm sure you'll do fine if you're used to the notion of "everything can kill me, oh god why?"

Elona is a roguelike with a mandatory tileset. Isgood! Another one with a learning curve to it, but one that yields much joy, if you don't mind being addicted to this kind of stuff. Don't forget to pick up the mp3 pack, too.